The present invention relates to melting, separation and disposal of mixtures of snow, ice, and solids. The invention further relates to melting, separation, decontamination, and disposal of contaminated mixtures of snow, ice and solids.
Industrial Projects may be undertaken in areas such as northern Alaska which experience frequent snowfall and freezing temperatures. As a result of these climactic conditions, ice and snow accumulate in exposed work areas. As ice and snow accumulate, any gravel or other solid debris on the ground in the work areas is frozen into the mixture as well. These accumulations hamper safe and free movement of personnel and equipment around the work area. Safe and efficient operation of the industrial progress therefore requires timely and cost-effective removal of accumulated frozen mixtures of ice, snow and solids from work areas, which may be many acres in size.
The problem is further aggravated by periodic, accidental discharges of materials such as oils or solvents into the work area which may occur despite the best precautionary measures. Discharged contaminants then end up as part of the frozen mixture of ice, snow and gravel, and result in the entire frozen mixture becoming contaminated. In order to prevent contamination of the surrounding environment, the entire frozen mixture must then be handled according to environmental regulations governing isolation and disposal of contaminated materials. The regulations are demanding and strict. The cost of compliance is very high, and may have a significant impact on the economic viability of an industrial project. At this time cleanup is handled by inefficient warm water nesting tanks and costly hauling of contaminated snow to designated locations where the contaminated material still has to be cleaned at a later date.
Various types of snow and ice melting equipment are disclosed in U.S. Pat. Nos. 634,021, 2,592,267, 2,991,784, 3,171,405, 3,277,885, 3,803,732, 3,866,340 and 4,506,656. Each discloses equipment for melting collected snow and ice, and then discharging the melted snow as a liquid or a slurry. U.S. '340 and '372 additionally disclose means for collecting snow from the surface and conveying it to a container for melting.
British Pat. No. 466 to Smallwood discloses a snow melting apparatus which, in addition to means for melting snow and discharging the resulting liquid, discloses a door for removing accumulated "sludge, etc." from the apparatus.
U.S. Pat. No. 818,072 to Blake discloses a snow melting machine which employs one or more grinding wheels to melt snow and ice which has been deposited in a hopper. Means are also disclosed for diverting entrained "stones and other obstructions" from beneath the grindstone, and for immediately discharging the diverted stones from the apparatus.
However, the above cited patents do not disclose machines which separate and collect contaminants which may be present in the frozen mixture. Further, although the '072 and the '466 patents provide for the removal of stones and sludge, respectively, neither provides for containment of contaminants while discharging collected solids.
Therefore a need exists for an ice and snow melting apparatus which is capable of melting frozen mixtures of ice, snow and solids, particularly at extremely cold temperatures, which is further capable of separating solids from the mixture, and which is also capable of separating and isolating contaminants which may be present in the frozen mixture to provide an effluent solid streams which are environmentally acceptable for discharge back into the environment. Further, the apparatus must be capable of handling large volumes of frozen mixtures efficiently and quickly, and of operating reliably in the extremely low temperatures encountered in arctic regions.